<?php

/**
 * JPGraph v4.0.3
 */

namespace lemon\JpGraph\Plot;

/**
 * File:		JPGRAPH_MESHINTERPOLATE.INC.PHP
 * // Description: Utility class to do mesh linear interpolation of a matrix
 * // Created:	 2009-03-09
 * // Ver:		 $Id: jpgraph_meshinterpolate.inc.php 1709 2009-07-30 08:00:08Z ljp $
 * //
 * // Copyright (c) Asial Corporation. All rights reserved.
 *
 * @param mixed $aFactor
 * @param mixed $aData
 */

/**
 * Utility function to do linear mesh interpolation.
 *
 * @param $aDat Matrix to interpolate
 * @param $aFactor Interpolation factor
 */
function doMeshInterpolate(&$aData, $aFactor)
{
	$m	 = new MeshInterpolate();
	$aData = $m->Linear($aData, $aFactor);
}

/**
 * Utility class to interpolate a given data matrix.
 */
class MeshInterpolate
{
	private $data = [];

	/**
	 * Calculate the mid points of the given rectangle which has its top left
	 * corner at $row,$col. The $aFactordecides how many spliots should be done.
	 * i.e. how many more divisions should be done recursively.
	 *
	 * @param $row Top left corner of square to work with
	 * @param $col Top left corner of square to work with
	 * $param $aFactor In how many subsquare should we split this square. A value of 1 indicates that no action
	 * @param mixed $aRow
	 * @param mixed $aCol
	 * @param mixed $aFactor
	 */
	public function IntSquare($aRow, $aCol, $aFactor)
	{
		if ($aFactor <= 1) {
			return;
		}

		$step = pow(2, $aFactor - 1);

		$v0 = $this->data[$aRow][$aCol];
		$v1 = $this->data[$aRow][$aCol + $step];
		$v2 = $this->data[$aRow + $step][$aCol];
		$v3 = $this->data[$aRow + $step][$aCol + $step];

		$this->data[$aRow][$aCol + $step / 2]			 = ($v0 + $v1) / 2;
		$this->data[$aRow + $step / 2][$aCol]			 = ($v0 + $v2) / 2;
		$this->data[$aRow + $step][$aCol + $step / 2]	 = ($v2 + $v3) / 2;
		$this->data[$aRow + $step / 2][$aCol + $step]	 = ($v1 + $v3) / 2;
		$this->data[$aRow + $step / 2][$aCol + $step / 2] = ($v0 + $v1 + $v2 + $v3) / 4;

		$this->IntSquare($aRow, $aCol, $aFactor - 1);
		$this->IntSquare($aRow, $aCol + $step / 2, $aFactor - 1);
		$this->IntSquare($aRow + $step / 2, $aCol, $aFactor - 1);
		$this->IntSquare($aRow + $step / 2, $aCol + $step / 2, $aFactor - 1);
	}

	/**
	 * Interpolate values in a matrice so that the total number of data points
	 * in vert and horizontal axis are $aIntNbr more. For example $aIntNbr=2 will
	 * make the data matrice have tiwce as many vertical and horizontal dta points.
	 *
	 * Note: This will blow up the matrcide in memory size in the order of $aInNbr^2
	 *
	 * @param  $ &$aData The original data matricde
	 * @param  $aInNbr Interpolation factor
	 * @param mixed $aIntFactor
	 * @param mixed $aData
	 *
	 * @return the interpolated matrice
	 */
	public function Linear(&$aData, $aIntFactor)
	{
		$step = pow(2, $aIntFactor - 1);

		$orig_cols = safe_count($aData[0]);
		$orig_rows = safe_count($aData);
		// Number of new columns/rows
		// N = (a-1) * 2^(f-1) + 1
		$p		= pow(2, $aIntFactor - 1);
		$new_cols = $p * ($orig_cols - 1) + 1;
		$new_rows = $p * ($orig_rows - 1) + 1;

		$this->data = array_fill(0, $new_rows, array_fill(0, $new_cols, 0));
		// Initialize the new matrix with the values that we know
		for ($i = 0; $i < $new_rows; ++$i) {
			for ($j = 0; $j < $new_cols; ++$j) {
				$v = 0;
				if (($i % $step == 0) && ($j % $step == 0)) {
					$v = $aData[$i / $step][$j / $step];
				}
				$this->data[$i][$j] = $v;
			}
		}

		for ($i = 0; $i < $new_rows - 1; $i += $step) {
			for ($j = 0; $j < $new_cols - 1; $j += $step) {
				$this->IntSquare($i, $j, $aIntFactor);
			}
		}

		return $this->data;
	}
}
